1. Field of the Invention
The present invention relates to a preparation for blood dialysis and a method for the production thereof. More particularly, it relates to a uniform powdery preparation for blood dialysis excellent in stability of storage and a method for the production thereof.
2. Description of the Prior Art
In the performance of blood dialysis, the patient's blood is purified in the artificial kidney. Inside the artificial kidney, the purification of the blood is effected by keeping the dialytic solution circulated in the artificial kidney, allowing the dialytic solution to contact the blood through the medium of a permeable membrane, and causing the waste matter and water accompanied by the blood to pass into the dialytic solution. The dialytic solution is closely and impartibly related to the improvement of the artificial kidney in performance. The acetate dialytic solution, the leader of the conventional dialytic solutions, is such that owing to the advance of the artificial kidney in quality, the acetic acid allowed to pass from this dialytic solution into the patient's vital organs has gained in quantity and the acetic acid causes the patient to suffer from such displeasing symptoms as headache and hypotension. Thus, it is giving place to the bicarbonate dialytic solution which exerts no appreciable burden upon the patient.
Unlike the acetate dialytic solution, the bicarbonate dialytic solution cannot be prepared as a single-component dope because sodium hydrogen carbonate present therein, on reaction with calcium or magnesium, gives rise to a precipitate. The bicarbonate dialytic solution, therefore, is prepared as a two-component composition comprising sodium hydrogen carbonate (principal solution) and a component containing calcium, magnesium, sodium, etc. (formulating liquid).
The principal component is prepared in the form of powder or solution and the formulating component in the form of solution. The amount of the principal component to be used is in the range of 500 to 1,000 g as powder or 10 to 12 liters as liquid and that of the formulating component in the range of 9 to 12 liters as liquid respectively per patient. In an institute abounding in patients, the work of transferring storage tanks of the dialytic solution exerts a heavy burden on workers. In an institute capable of performing dialysis simultaneously on 20 patients, for example, the dopes of both principal component and formulating component in a total amount enough for 40 patients (about 380 to 480 kg) must be transferred. The institute suffers also from the problem that the transfer and storage of these dopes call for engagement of human labor and require preservation of floor spaces.
In the light of the true state of affairs described above, efforts are directed to decreasing the weight of the dialytic preparation by producing this preparation in the form of powder. JP-B-58-27,246 (1983), for example, discloses as means for uniform dispersion of a liquid acid a method for producing an electrolytic compound powder of the bicarbonate dialysis quality by powder mixing using a microfine powder of sodium chloride acidified with acetic acid. JP-A-62-30,540 (1987), concerning the production of a preparation for dialysis using sodium acetate as a principal component, discloses a technique for decreasing dispersion of the contents of such microconstituents as MgCl.sub.2 .multidot.6H.sub.2 O and CaCl.sub.2 .multidot.2H.sub.2 O in the dialytic solution obtained from a dialytic preparation having sodium acetate as a principal component by intimately mixing these microconstituents with sodium acetate and water and converting the resultant mixture into fine powder.
In the powdery preparation for dialysis of the type using sodium hydrogen carbonate as a principal component, calcium chloride and magnesium chloride exhibit a deliquescing property and sodium chloride possibly acquires enhanced hygroscopicity in the presence of calcium chloride and magnesium chloride. This preparation, therefore, undergoes deliquescence or solidification during the course of production, transfer, or storage and entails the disadvantage that it betrays notable dispersion of composition and inferior stability during protracted preservation. Further, since this preparation uses acetic acid as a liquid acid, it possesses a high vapor pressure and readily succumbs to volatilization even when it is adsorbed on an inorganic salt, and lacks stability and workability. In recent years, the practice of curbing possible variation in the blood sugar level by adding glucose to the dialytic solution has been finding acceptance in the field of clinical medicine. None of the preparations heretofore produced for dialysis has proved to be capable of retaining stability in protracted preservation.
An object of this invention, therefore, is to provide a novel powdery preparation for dialysis and a method for the production thereof.
Another object of this invention is to provide a powdery preparation for dialysis, which excels in the ability to withstand the impact of transfer and storage and in the maintenance of uniformity and stability of powder production.